Outdoor lamp base



FIG. 1 is a perspective view of the new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a front plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

We claim the ornamental design for an outdoor lamp base, as shown and described. 